A post on Mayweather’s Instagram account predicted he would make a large amount of money on another ICO and a post to Twitter said: “You can call me Floyd Crypto Mayweather from now on.”

The two men touted the offerings to their millions of social media followers without disclosing the payments, according to the settlement.

“This is a game changer here. Get your CTR tokens now!” Mr Khaled wrote in one post cited by the SEC.

The SEC said Mr Khaled agreed to repay the $50,000 he received for the endorsement, as well as a $100,000 fine and interest.

Mr Mayweather will repay the $300,000 he received, as well as a $300,000 fine and interest.

SEC Enforcement Division Co-Director Steven Peikin said the cases were a reminder that investors should “be sceptical of investment advice posted to social media platforms, and should not make decisions based on celebrity endorsements”.

“Social media influencers are often paid promoters, not investment professionals, and the securities they’re touting, regardless of whether they are issued using traditional certificates or on the blockchain, could be frauds,” he said.